What is the best deck that you can possibly make wit out using codes?

There is no "best" deck. Every deck has it's individuality. That's what was so great about the first gen of Yu Gi Oh cards. You got'a struggle to built a competittive deck. If you want a pointer, I can post an easy-to-built recipe, but you got'a get your own style in order to win.

[Effect Monsters]
2# A Cat of III Omen
1# Blast Sphere
1# Cyber Jar
1# Dark Necrofear
3# Giant Germ
1# Helpoemer
1# Marshmellon
1# Morphing Jar
3# Needle Worm
1# Sangan
3# Spirit Reaper
2# Vampire Lord

[Spell Cards]
1# Card Destruction
1# Different Dimention Capsule
1# Emergency Provisions
1# Giant Trunade
1# Gravekeeper's Servant
2# Messanger of Piece
1# Swords of Revealing Light
1# Toll
1# Wave-Motion Cannon

[Trap Cards]
1# Astral Barrier
1# Gravity Bind
1# Metal Reflect Slime
1# Ring of Destruction
2# Secret Barrel
3# Skull Invitation
1# Spirit Barrier